Report of the joint Norwegian-Russian acoustic survey on blue whiting, spring 1996

Abstract

In March/April 1996 the sixth Norwegian-Russian joint acoustic survey on the blue whiting spawning stock was carried out. The bank and shelf edge area to the west of The British Isles was covered from south to north by a Norwegian vessel and from north to south by a Russian vessel. Due to time difference between the coverages by the two vessels it was decided not to combine the data for a common estimate. Although there was difference in the observed abundance, and the stock some below than last year`s level, it was found to be in a rather stable condition. The three yearclasses, 1993, 1994 and 1995 dominated in the total estimate of the blue whiting stock. The hydrographic situation in the surveyed area was sligthly different from 1995, i.e. the temperature being some higher. Due to this the peak of spawning was earlier and hence the postspawning migration from south to north about a week earlier than usual.